Amanda Knox talks to reporters during her first press conference since leaving Italy

It was in glaring contrast to the agonising ordeal of the Kercher family, still desperate for justice for the 21-year-old student found with her throat cut in the house she shared with Knox in Perugia in November 2007.

Last night they said they would support an appeal by Italian prosecutors against Knox’s acquittal.

Amanda Knox broke down as she landed in the US for the first time in four years

A lawyer for the only person still behind bars for the killing, small-time drug-dealer Rudy Guede, 24, from the Ivory Coast, has said he will seek a retrial. Knox’s prison ordeal came to an end when an appeal court in Perugia, Italy, acquitted her and former lover Raffaele Sollecito, 27, of the murder after 11 months considering the original verdict.

Angry crowds outside, convinced of the couple’s guilt, had shouted at Knox: “Jump on your private plane and go home.”

Mr Clifford said last night: “Although she has convinced the Italian courts she is innocent there are still many members of the public who aren’t so sure.

“She’s got to win over the hearts and minds of the public. The more successful she is at that the more money she’ll make from film, TV and book deals, which could be from five to £15million.”

Amanda Knox leaving Rome Airport earlier the same day

Mr Clifford suggested she could help win over the public by donating some of her earnings to Meredith’s Surrey-based family, or a charity of their choice. “I think it would be a good move for her,” he said. “Whether or not they [the Kercher family] choose to accept it is another matter, or she could donate it to a charity of their choice.”